I'm not fully understanding your question... Have you used any of the Studies or Strategies that come with Thinkorswim and/or studied the Thinscript code within...??? There is no Start/Stop button, although there is an option to control whether or not a specific Study/Strategy that you have loaded will paint on your Charts... This feature is primarily for testing and debugging purposes...
As for referencing other scripts from within a Study, such calls will return whatever plot data your reference has requested, whether boolean or actual numeric data... It would be beyond the scope of this topic to give a complete overview of how Thinkscript interacts with Thinkorswim and only independent experimentation will help with understanding...